I hope some one can help! I have a ton (300' +) of LED lights. They are the old variety which look like strips of 3-4 lights on a plastic backing- some look like dominoes. Last year we covered our art cart in them and ran them off a 12 V deep cycle. This year we are doubling the amount of lights. I was wondering if it was necessary to include another battery or will one do just fine. I also have red LED lights. I read on the net that red are different watts than white???? Can I still connect them to the white ones without problems? I really don't feel comfortable calculating Ohm's Law or the like. Any advice would be greatly appreciated!

I hope some one can help! I have a ton (300' +) of LED lights. They are the old variety which look like strips of 3-4 lights on a plastic backing- some look like dominoes. Last year we covered our art cart in them and ran them off a 12 V deep cycle. This year we are doubling the amount of lights. I was wondering if it was necessary to include another battery or will one do just fine. I also have red LED lights. I read on the net that red are different watts than white???? Can I still connect them to the white ones without problems? I really don't feel comfortable calculating Ohm's Law or the like. Any advice would be greatly appreciated! We have a battery charger that is set to trickle to charge the battery at camp.

Can you be more specific as to the power consumption per foot/meter? RGB or all single color? What SMD do you have-any part number would be a great help? Picture? Did you have problems last year? How charged was your battery at the end of the night? Can you do a test now and leave them set up? You should empirically determine what you need now, but you can calculate it....

Thanks for responding! We have all different kinds of LED light strip modules that we got second hand from someone who owns a sign company. Some of them look like the ones in this photo- some have 3 lights, others four, and some that look like dominoes.http://www.lights-expert.com/b2b/lighti ... ip_47.html

Last year they worked pretty well except that the splices between some were loose. I have a voltometer that I take out to check and the charge seemed good. we are going to use two separate deep cycles this year.Decided that today! Just want to be sure that I am prepared for any unseen problems. Thanks!

You really should get a multimeter. It will have V which can tell you how low your battery is getting. It will also have Amps, you can connect it to the setup of all your strips, maybe on say the 20A scale. That and the Amp-hour rating of the battery(s) will tell you how many hours they will run. We can't tell you by looking at a picture of a bunch of different kinds of strips.

Yep, gonna need WAY more information before anyone even begins to help you on this. 300+ strips? Or 300+ LEDs total? How many amp-hours is your battery or batteries? You need to monitor the voltage in your batteries to make sure they are not getting too low, because that affects the batteries life span.

According to the charts I could find in my documents, if your battery is getting down to 12.1-12.2 volts, that is around 50% and needs to be recharged. 12.7 volts is fully charged.....

LEDs produce such a low draw that if you system didn't blow up last time, doubling the number isn't going to hurt it. It'll just drain the battery that much faster. We once drove a 200 pound battle bot through a brick wall using 12 volt sealed lead acid batteries and and only chose them because deep cycle batts don't discharge fast enough. You shouldn't have a problem with power.

"The Red Baron is smart.. He never spends the whole night dancing and drinking root beer.. "-The WWI Flying Ace

I think he's more worried that his batteries will be sufficient to last long enough, not that the batteries will suffer from a higher discharge rate.

In that case you will need to calculate out the current draw of your LEDs and see if your battery AH rating is sufficient for the amount of time you want to use the batteries. Try to aim for only 50% discharge on your batteries before recharging them if you want to get the most out of them. If you're doubling the number of lights--of the same kind--it'll probably double the amount of current being used. If it's a different variety of LED, look up the manufacturing specifications and calculate from there.

"The essence of tyranny is not iron law. It is capricious law." -- Christopher Hitchens

Chiroptera wrote:I have a ton (300' +) of LED lights. They are the old variety which look like strips of 3-4 lights on a plastic backing- some look like dominoes. Last year we covered our art cart in them and ran them off a 12 V deep cycle. This year we are doubling the amount of lights.

Oh, let's see. I'll guess there's about 4 LED's per foot, so with 600', that's 2,400 LED's. If they're just one color, figure they use about 20mA each at an average of, say, 3 volts, so that's 60mW each which is 0.06 watts * 2,400 = 144 watts. They probably just use a resistor to regulate from 12V which I'd say is about 75% efficient. 144 watts / 75% = 192 watts (e.g. 192 watts in * 75% efficiency = 144 watts out).

So the deep-cycle battery is probably something like 90 amp-hours, and you don't really want to run it past 25% capacity, so you can use about 68 amp-hours or so. At 12 volts, 68 amp-hours * 12 volts = 816 watt-hours. So your 192 watts of lights could run for 4 hours and 15 minutes.

If they're RGB color-changing LED's, then red, green, or blue is one emitter per LED, so that's the same at 192 watts = 4.25 hours. If you do a solid color like yellow (red+green), cyan (green+blue), or magenta (blue+red), then that's 384 watts so you only get 2.1 hours. And if you turn red, green, and blue all on, you get white but that's 576 watts or 1.4 hours.

Thank you all so very much for responding! I should have paid way more attention in the 1.5 years of Physics classes. Anyway- I had an electrical engineer friend come over and assess the situation. Right now I have 750 LED strip lights on the top part of the car. Each strip has either 3 or 4 individual lights. About a third are red, the rest are white. They are running on an Optima deep cycle yellow top. The strips are connected in parallel - but the individual lights inside each strip are connected in series- each light has it's own resistor. Pretty neat. We measured the amps for each type of LED with a multimeter- so I was able to choose the most efficient type. Once all the lights are completed I will use the same method to test both strings- that way I can see how many hours I should have, If need be I will have to buy and mount another battery. I do use the multimeter all the time on the playa. It is a girl's best friend. The cart is electric and I have a digital meter which also measures the 36 V which run the car.

Again- thank you so much for the calculations and all the information. It is greatly appreciated and I will use the formulas for the future. Science rocks!

See you all out on the playa! Look for a glowing fur Chinese dragon golf cart so I can give you a hello and a hug in person! )'(